Arthritis at the base of the thumb is one of the most common sites of osteoarthritis in the hand. Thumb arthritis is more commonly seen in women than in men, and typically occurs after age 40. Here is a closer look at the details of the condition, as well as its symptoms, diagnosis, treatment, and prognosis.
Anatomy and Mechanics of the Thumb Joint
The thumb joint is formed as a saddle-shaped coupling between the trapezium (one of the wrist bones) and the first metacarpal (first bone of the thumb). This joint allows the thumb to move, pinch, and grip.
Osteoarthritis occurs when the cartilage that covers the ends of the bones begins to wear down. The exact cause of thumb arthritis is unknown, but genetics or previous trauma (including fractures or dislocations) may predispose individuals to the development of this type of arthritis. Without cartilage to act as a cushion, the bones become rough and grind over each other, which can cause further damage to the joint.
Symptoms of Thumb Arthritis
According to Dean G. Sotereanos, MD, orthopaedic surgeon at Orthopedic Specialists – UPMC, pain is the most common symptom of thumb arthritis and typically occurs at the base of the thumb with gripping and pinching activities such as opening a jar or bottle, turning a door handle, twisting a key, or snapping the fingers. Other symptoms may include swelling, stiffness, or tenderness at the base of the thumb.
As symptoms worsen, pain may occur even while the thumb is at rest. The strength and range of motion of the thumb will often decrease as a result. In severe cases, misalignment of the thumb occurs with the presence of a bump over the joint. This may affect the joint above, causing a bent-back appearance (hyperextension).
Thumb Arthritis Diagnosis
A diagnosis is made after a thorough medical history is taken and a physical examination is completed. Specific movements and tests are then performed in an attempt to accurately reproduce the symptoms at the base of the thumb.
X-rays can confirm the diagnosis, typically revealing cartilage loss in the joint. However, for reasons that are not always clear, the severity of pain doesn’t necessarily correlate with cartilage loss shown on x-rays.
Thumb Arthritis Treatment Options
Patients in the early stages of thumb arthritis will usually respond to nonsurgical treatment. Anti-inflammatory medications and splinting may also help alleviate pain. In addition, a corticosteroid injection directly into the joint can often provide pain relief.
For those who find nonsurgical treatment ineffective, as well as for patients with advanced thumb arthritis, surgical treatment is often recommended. These are usually done on an outpatient basis and include joint arthroplasty, joint fusion, and bone realignment. A tendon interposition arthroplasty may be performed with removal of the arthritic bone (trapezium) and reconstruction of the joint with a tendon graft or artificial substance.
Recovery from Thumb Arthritis Surgery
If surgery is necessary, a thumb splint is applied after the procedure and will remain in place for six to eight weeks. A rehabilitation program often involves physical therapy to help regain hand movement, control, and strength. Patients can expect a full recovery typically within three to six months after surgery.